> ## Documentation Index
> Fetch the complete documentation index at: https://praison.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Hook Plugin Protocol • Rust AI Agent SDK

> HookPluginProtocol: Lifecycle hook plugin protocol

# HookPluginProtocol

> Defined in the [**plugins**](../modules/plugins) module.

<Badge color="orange">Rust AI Agent SDK</Badge>

Lifecycle hook plugin protocol

```mermaid theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
%%{init: {'theme': 'base', 'themeVariables': { 'primaryColor': '#8B0000', 'primaryTextColor': '#fff', 'primaryBorderColor': '#710101', 'lineColor': '#189AB4', 'secondaryColor': '#189AB4', 'tertiaryColor': '#fff' }}}%%

graph TD
    event["Event Trigger"] --> hook["Hook: HookPluginProtocol"]
    hook --> decision{"Decision"}
    decision -- "Allow" --> proc["Process"]
    decision -- "Deny" --> block["Block"]
    style hook fill:#189AB4,color:#fff
    style event fill:#8B0000,color:#fff
    style proc fill:#8B0000,color:#fff
    style block fill:#8B0000,color:#fff
```

## Methods

### `before_agent`

```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
fn before_agent(&self, _agent_name: &str, _input: &str) -> Result<Option<String>, String>
```

Called before agent execution

**Parameters:**

| Name          | Type   |
| ------------- | ------ |
| `_agent_name` | `&str` |
| `_input`      | `&str` |

## Source

<Card title="View on GitHub" icon="github" href="https://github.com/MervinPraison/PraisonAI/blob/main/src/praisonai-rust/praisonai/src/parity/plugins.rs">
  `praisonai/src/parity/plugins.rs` at line 0
</Card>

***

## Related Documentation

<CardGroup cols={2}>
  <Card title="Rust Hooks" icon="anchor" href="/docs/rust/hooks" />

  <Card title="Rust Events" icon="bolt" href="/docs/rust/events" />

  <Card title="Rust Callbacks" icon="phone" href="/docs/rust/callbacks" />

  <Card title="Rust Plugins" icon="plug" href="/docs/rust/plugins" />
</CardGroup>